Rear bumper diffuser for a vehicle



FIG. 1 is a left, perspective view of a rear bumper diffuser for a vehicle according to our design, the right, perspective view being mirror symmetrical; and,

FIG. 2 is a front view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a rear bumper diffuser for a vehicle, as shown and described. 